1. Field of Invention
The present invention relates to a flat lamp. More particularly, the present invention relates to a conductive composition used in a flat lamp.
2. Description of Related Art
Flat lamp featured by its luminescence efficiency, uniformity and large-area luminescence is widely employed in backlight module of liquid crystal display or other devices. Flat lamp comprises an upper substrate and a lower substrate that cooperatively form a panel-like structure. Each of the outer surfaces of the upper substrate and the lower substrate has an electrode layer disposed thereon. Each of the inner surfaces of the two substrates has a fluorescence layer disposed thereon. The upper substrate and the inner substrate are held together with a space therebetween. When a voltage is applied to the electrode layers, the gas within the space will be excited and thereby emitting an UV light. The fluorescence material in the fluorescence layer would absorb the UV light and convert the same into a visible light with a specific wavelength range. As such, the flat lamp outputting the visible light can be used as a flat light source.
The mixture for forming the electrode layer of the flat lamp is composed of a metal powder, a glass powder and an organic solvent. The glass powder functions as a binder for binding the metal powder with the substrate. Conventionally, the sizes and amounts of the glass powder and the metal powder contained in the electrode layer are about the same. Therefore, a portion of the glass powder may exist at the surface of the electrode layer. Generally, a high temperature process is performed after the electrode layer is formed on the glass substrate, so that a fluorescence layer is formed on the other side of the glass substrate. During the high temperature process, the glass substrate is disposed on a supporting carrier (supporter) with the electrode layer contacting the supporter. In this case, the glass material adjacent to the surface of the electrode layer would be softened and thus binds with the supporter thereunder. Once the electrode layer and the supporter are bound together, it is very difficult to separate the glass substrate from the supporter after the glass substrate, the electrode layer and the fluorescence layer are cooled down. As such, the glass substrate and the supporter would often crack during the separating step. To avoid the cracking issue mentioned above, conventional approach for manufacturing a flat lamp includes the steps as follows. First, a fluorescence layer is formed on the substrate, and the substrate having the fluorescence layer formed thereon is shaped into a corrugated structure. Afterward, two substrates are assembled together. In this case, since the substrate is corrugated in shape, the electrode layer can only be formed by means of soaking or spraying. Then, a baking process is performed to complete the processes for manufacturing the substrate of a flat lamp. However, the electrode layer thus obtained usually has a thickness of about 200 μm to 250 μm, which would increase the production cost. In addition, the electrode layer thus obtained usually has the drawback of uneven thickness, which would jeopardize the product quality. Therefore, a novel method for manufacturing a flat lamp is necessary to be provided to address problems mentioned above.